A magnetic absolute position sensor is known in the state of the art from the document DE 10 2007 039 051 A1.
The sensor described therein is capable to determine, on the one hand, an angular posture of a permanent magnet and, on the other hand, to count a number of turns of the permanent magnet as well as to store a value, which corresponds to the number, in a non-volatile memory. The absolute position of the permanent magnet can be determined from the value, which corresponds to the number, and the actual angular posture.
The known sensor is realized by a utilization of different technologies, namely the CMOS technology and the FRAM technology, which is employed for the non-volatile data memory, in an integrated circuit. The non-volatile data memory is particularly a FRAM data memory because this allows a very high number of storage cycles in contrast to data memories, which are based on other technologies, for example the CMOS technology, and thus ensures a sufficient life time of the sensor in this respect.
The realization of an integrated circuit on the basis of both technologies is however complex and expensive.
The alternative employment of two separated integrated circuits is not always possible, because the data traffic between the two integrated circuits is more complex—and thus slower—and more energy-intensive. For applications without external energy supply, in which a high data traffic must be fast and not sufficient energy is available for the data traffic between two separate integrated circuits, one will thus not be able to dispense with the formation of a single integrated circuit on the basis of two technologies, even if this is more complex and more expensive.
Aggravatingly, it is added that the application possibilities of the FRAM memory is limited in view of its temperature stability, such that in applications involving higher temperatures, the employment of the known sensors is not possible.